Engineer&#39;s brake-valve.



No. 725,020. PATENTED APRl 14, 1903. R. 0. AUGUR & H. P. BICKEL.

ENGINEERS BRAKE VALVE.

APPLIOATION FILED MAR. 31, 1902. BENEWBD JAN. 5, 1903. .Ho MODEL. aSHEETS-SHEET 1.

mofa-urna.. wswnmon, a c.

110.725,02@ AMmmm APR.'14,.1903.

R c AUGUB. a; H F BIGKEL BNGINBER'S BRAKE VALVE.

APPLICATION FILED MAR. 31, 1902. BENEWED JAN. 5. 1903.

3 SHEETS-SHEET 2.

4"F0 MODEL.

{dirgli/366185' s ns-raws cn.. no1-udma., wwwa s srmmwsnrm 3.

PATENTED APB.. 14, 1903. R. C. AUGUR n H. P. BIGKEL.

y ENGINEERS BRAKE VALVE. APPLIGATION FILED MAB. s1, 1902. BENEWBD JAN.s, 190e.

F0 MODEL.

ff/Lmeses;

N ITED Stamps Aentrenar einen..

ROBERT C. AUGUR, OF WATERTOWN, NEW YORK, AND HENRY E. BTOKEL, OFPLAINEIELD, NEW JERSEY, ASSIGNORS TO NEW YORK AIR BRAKE COMPANY, OE NEWYORK, N. Y., A CORPORATION OF NEW JERSEY.

ENGINEERS BRAKE-VALVE SPECIFICATION forming part of Letters Patent No.725,020, dated April 14, 1903.

Application tiled March 31,1902. Renewed January 5. 1903. Serial No.137,947. (No model.)

To @ZZ whom. it may concern:

Be it known thatwe, ROBERT O. AUGUR, of Watertown, county of Jefferson,and State of New York, and HENRY F. BIGKEL, of Plaintield, county ofUnion, and State of New Jersey, have invented an Improvement inEngineers Brake-Valves, of which the following description, inconnection with the accompanying drawings, is a specication, like letioters on the drawings representing like parts.

The present invention relates to an engineers brake-valve,and isintended as an improvement on the type of brake-valve forming thesubject of Letters Patent to Vaughan i5 and McKee, No. 504,290, datedAugust 2Q,

The valve of the Vaughan and McKee patent has proved satisfactory inpractical use; but there are certain conditions which somezo times maycause the valve to fail to `give the proper automatic operation inshutting oif the escape of air from the train-pipe in applying thebrakes or may cause the automatic shutting oi'l to take place at asomewhat-different pressure from that which would be produced in thenormal or intended operation of the apparatus; and the present inventionmainly consists in novel features of construction and arrangementwhereby such abnor- 3: mal operation of the apparatus is renderedimpossible.

The engineers valve of the Vaughan and McKee patent, in which thepresent invention is embodied, is characterized by a cut- 5 off valvefor closing the escapepassage through which the train-pipe air ispermitted to escape in the operation of applying the brakes, whichcut-oft valve is operated by a piston subjected to train-pipe pressureupon 4o one side and upon the other side to the pressure ot' adeterminate quantity of air which normally is under a pressure equal tothat in the train-pipe and which when the trainpipe pressure is reducedcauses the cut-off piston to be moved a distance substantiallyproportional to the reduction in train-pipe pressure. This is becausethe reduction in train-pipe pressure caused by permitting the air toescape from the train-pipe leaves the o determina quantity of air whichis confined in a small chamber or reservoir with a preponderatingpressure, which causesthe piston to move,and in such movement of thepiston the determinate quantity ot' air following it expands, and thusdiminishes in pressure in proportion to the movement of the piston,which movement will thus increase in eX- tent as the train-pipe pressurefalls by the escape of air from the train-pipe and as the pressure ofthe coniined body of air falls on 6o account of the expansion involvedin following up the movement of the piston.

In the valve of the Vaughan and McKee patent the small chamber is openedto the atmosphere and the contained air is substantially Whollydischarged in the operation of releasing the brakes, which is done byadmitting air from the main reservoir intothe trainpipe, and in thisreleasing operation the trainpipe pressure thus acts substantially unop-7o posed upon the cut-oi-actuating piston and moves it back to normalposition-that is, to the starting-point of its movement-forautomatically closing the escape-passage from the train-pipe in the nextapplication of the brakes. Then in order again to provide a body of airin the small chamber under pressure equal to train-pgpe pressure for thepurpose of actuating the piston in the next application ot' the brakesthe valve apparatus is provided 8o with an equalizing-passage connectingthe spaces at the two sides of the piston and controlled by the mainhand-operated valve in such manner that said equalizing-pass'age isopened and affords a connection between the train-pipe and the smallchamber only when the main valve is in ruiming position-that is, whenthe train-pipe is in communication with the main reservoir through anexcess-pressure or feed valve. This equalizng-passage 9o of course hasto be closed during an application of the brakes in order that the airmay be entrapped in the small chamber to actuate the piston inaccordance with the reduction of train-pipe pressure, saidequalizing-passage being closed by the main hand-operated valve when thelatter is moved by the engineer to the position for opening theescapepassage from the train-pipe, and thus causing the brakes to beapplied. loo

The above-described means for effecting the return movement of thepiston to normal position and for recharging the small chatnber andmaintaining the pressure therein equal to that in the train-pipe whilethe valve is in running position are such that under certain conditionsor by certain possible manipulation the automatic operation of thecut-off valve may be prevented or may be caused to take place at apressure in the train-pipe other than what would b'e produced in theregular or normal automatic operation of the cut-olf valve; and thepresent invention consists mainly in novel means for diminishing thepressure in the small chamber to permit the piston to be restored tonormal position and for recharging the small chamber when the piston isin normal position in order to provide the body of air requisite for theproper actuation of the piston in the next application of the brakes.The appliances employed for this purposein accordance with the presentinvention are characterized by the absence of any equalizing connectionaround the piston and by not having the recharging-passage for the smallchamber controlled in any way by the main hand-operated valve, theresult being that, except in the operation of applying the brakes, thetrain-pipe air is always. maintained with a pressure preponderating overthat in the small chamber, and thus insures the return of the piston toand its retention in its normal position up to the time when the valveis operated to produce the next application of the brakes. l

Figure l is a side elevation of an engineers brake-valve embodying thisinvention. Fig. 2 is a longitudinal section thereof on line x2- ot Fig.3; Fig. 3, a transverse section thereof on line 003, Fig. 2. Fig. 4 is aplan ofthe face of the main hand-operated valve. Fig. 5 is a transversesection on line m5, Figs. l and G. Fig. 6 is a plan of the valve-seat.Fig. 7 is a sectional plan of the valve on line x7, Fig. 2;

Fig. 8, a longitudinal section showing the operative relation of some ofthe parts when in running position, and Fig. 9 is a similar view showingthe relation of said parts in a service application of the'brakes. Figs.8 and 9 do not show the exact structural form of the ports or passages,but are in the nature of diagrams to show the operative relations moresimply than if the actual construction were represented. Figs. 10, 1l,and l2 illustrate modifications in construction which may be employed incarrying out the invention.

For an understanding of the present invention it will be necessary todescribe the mode of operation ot' the main parts of the valve, which donot in themselves constitute the present invention, and are shown assubstantially the same as in the Vaughan and McKee patent beforereferred to.

As is well known, the operation of the familiar automatic airbrake,apparatus involves the charging of the train-pipe with air to releasethe brakes and the maintenance of a substantially constant pressure,usually seventy pounds to the square inch, in the train-pipe while thetrain is running withA the brakes released. To make a graduated orservice application of the brakes, air is permitted to escape from thetrain-pipe, so as to reduce the pressure therein, and the brakes areapplied with increasing force as the train -pipe pressure diminishesuntil the maximum braking-force is attained, which requires a reductionin'train-pipe pressure to fifty pounds or somewhat less. To apply thebrakes promptly, the train-pipe pressure is reduced quickly by opening alarge vent from the train-pipe, which causes the brakes to be appliedwith maximum braking force almost instantly. This is called an emergencyapplication of the brakes.

The engineers brake-valve is an apparatus for enabling the engineer togovern the adomission ot' air to and its discharge from the train-pipetocause all the desired opelations of the brakes to take place, and thebrakevalve in which the present invention is embodied contains ahand-operated valve ct, adapted to be manipulated by the engineer bymeans of a handle h, which valve when at the extreme left-hand positionwith relation to a person facing the valve, as seen in Figs. l and 2,opens a large passage between the main air-reservoir on the locomotiveand the train-pipe, and thus charges the train -pipe to release thebrakes. The valve apparatus has passages c d, adapted to be connectedwith the main reservoir on the locomotive and with the train-pipe,respectively. The pressure is usually maintained in the main reservoirconsiderably higher than that normally required in the train-pipe whenfully charged, and after the brakes are released the valve ct is placedin running position, in which it alords a connection from the mainreservoir to the train-pipe through a reducingvalve or pressureretaining valve e. (See Figs. 5 and 6.) The running position of thevalve a is a short distance to the right of thef'release position, andin connection with the engineers handle b there is a notched segment b2to facilitate the placing of the handle and valve in the variouspositions required in the operation of the brakes.

For graduated or service applications of the brakes the valve a is movedby the handle l) to the right from the running position a greater orless amount, according to the degree of braking force desired, thismovement of the valve cutting off the connection between the mainreservoir and the train-pipe and establishing a connection .from thetrainpipe to the atmosphere through which air may escape from thetrain-pipe to reduce the train-pipe pressure and cause the brakes to beapplied with a force depending upon the amount of train-pipe-pressurereduction.

For emergency application of the brakes the valve a is thrown by thehandle b to the IOO roi;

IIO

extreme right-hand position, and thus opens a large escape-passage fromthe train-pipe to the atmosphere, thus giving a sudden reduction of thetrain-pipe pressure, which causes the brakes to be promptly applied withfull force. The ports and passages by which these effects are producedare as follows: The main-reservoir connection c communicates by thepassage c2 (see Fig. 5, shown also in dotted lines, Fig. 1) 'with thespace in the valve-chest f, so that the full main-reservoir pressure isat all times maintained in the valve-chest and upon the outside ot thevalve a. The valve-seat f2, upon which the valve a works, is providedwith a port or opening g, communicating with the space in the main bodyof the valve apparatus, which is in constant communication with thetrain-pipe through the passage d. A portion of the said space in thebody of the valve is made as a cylinder c2, in which works the piston h,which operates to cut oit or stop the escape ot' air from the train-pipeautomatically in the service application of the brakes, as Will beexplained. The said piston his thus constantly subjected to train-pipepressure on its left-hand side, tending to move it to the right-hand endofthe cylinder g2.

In order to release the brakes, the movementtof the valve a to theextreme left-hand position uncovers the right-hand portion of theopening g, and thus admits the air directly from the valve-chest f andmain reservoirinto the body of the valve and train-pipe to recharge thelatter and release the brakes.

In the running position the connection is made from the train-pipe tothe main reservoir through the excess pressure or feed valve c. The saidexcess-pressure valve e is contained in a passage c2, leading from thevalve-chest f, and the air after passing the said valve c enters apassage c3, having ports e4 leading to the valve-seat f2. The valve ahas near its right-hand end pockets or cavities a2, which in the runningposition of the valve, as shown in Fig. 2, connect the ports e4with theopening C, so that in this position air may pass to the train-pipe asmay be required to make up for leakage and to retain the normal pressurein the train-pipe, said air passing from the main reservoir andvalvechestf through the passage c2, past the valve e, and thence throughthe passages e3 c4 and cavities a2 in the valve into the opening c, andthence through the body of the valve into the train-pipe connection d.

A slight movement of the valve a to the right from the running position(shown in Fig. 2) will carry the pockets a2 ol from the opening g in thevalve-seat, andthus close the connection last described from the mainreservoir through the valve c to the trainpipe, and in this position allot' the passages with one exception, which will be described later on,are closed or blanked, this position being known as the lap position ofthe valve, which, however, takes no part in the regular operation of thebrake apparatus. In all further movement of the valve a to the rightthroughout its entire range of movement the communication from the mainreservoir, either direct or through the valve e, t0 the train-pipe iscut off. Such further movement of the valve to the right causes thebrakes to be applied by permitting air to escape from the trainpipe, asfollows: The valve apparatus is provided with a main eX- haust-passaget', leading to the atmosphere and having a port-opening t2 in thevalveseat f2 under the valve a. When the handle b is moved to the rightto one of the serviceapplication notches, communication is establishedbetween the opening g from the body communicating with the train-pipe t0the exhaust-passage i by a passage a3 in the valve d, havingport-openings a4 a5 in the face of the valve that travels on thevalve-seat. The

opening a5 comes into connection with the exhaust-port t', and theopening a4 passes the right-hand edge of the movable cut-off slide 7o,so that the air is permitted to escape from the train-pipe through theexhaust-passage i.

The escape ot air from the train-pipe is automatically stopped by thecut-ofi:l slide k when the train-pipe pressure is reduced to the desiredamount, depending upon the distance the engineer moves the handle htoward the right in the range of service positions. This automaticmovementof the cu t-ott slide 7a is produced by the piston h, the rod orstem h2 of which is connected with the slide 7s by the lever 7a2,pivoted at 7c3, the connection being such that a movement of the piston7L toward the left produces a much smaller movement of the slide 7ctoward the right.

The space in the end of the cylinder g2 at the right-hand side of thepiston h is in constant communication through the passage 'm2 with asmall reservoir or chamber m, (see Figs. l, 8, and 9,) said chamberbeing of a capacity proportional to the capacity ot' the cylinder g2, sothat a quantity of air in said chamber at a given pressure-for example,

approximately the normal train-pipe pressure- Will fall in pressure byexpansion in the desired rate as the piston h moves toward the left, andthus aiords space inA the cylinder at the right hand of the piston forthe air in the small reservoir 'm to expand into.

Assuming that air is contained in the chamber 'm at train-pipe pressurejust before the movement of the valve a to produce a service lapplicationot the brakes, as has been described, it Will be seen thatwhen the port a4 of the valve has been moved beyond the righthand edgeof the slide 7c air Will escape from the train-pipe and the train-pipepressure will gradually fall as t-he air continues to escape. This Willreduce the pressure upon the lefthand side of the piston h, thus leavingthe vpressure in the small reservoir on the righthand side inpreponderance and causing the piston h to move toward the left, In thismovement the pressure ou the right will fall IOO IIO

mal position.

by expansion of the air, and therefore the movement Will continue onlyas the trainpipe pressure continues to fall, and the eX- tent of themovement Will depend upon the amount of fall of train-pipe pressure.Assuming that the port a4 was moved only a slight distance beyond theright-hand edge of the slide 7c, a comparatively small movement of thevpiston h toward the left, such as would result from a comparativelysmall reduction in train-pipe pressure, Would move the slide 7c farenough to the right to close the port a4, so that the further escape ofair from the train-pipe Would be automatically stopped; but if the valved had been moved farther toward the right a longer movement of thepiston and of the slide 7c Would be required before the port would beclosed, and consequently a greater reduction in train-pipe pressurewould be elfected before the automatic stopping of the escape of airfrom the trainpipe, and thus the different pressures that may be desiredare attained by moving the handle ZJ dierent distances in the range ofservice-application positions.

The movement of the valve a promptly to eXtreme right-hand positionaffords a large connection from the opening gto the exhaustport t'through the passage a6 in the valve, Which is independent from thepassage a2 and has port-openings a7 a2, whichv are brought,respectively, over the openings g and 1,'2 when the valve arrives atextreme right-hand position, and thus afford a large vent from thetrain-pipe, as is required for producing an emergency application of thebrakes.

The parts thus far described may be of the same construction as adoptedin apparatus of this general type heretofore, and are shown assubstantially the same as in the valve made -under the Vaughan. andMcKee patent for 'actualservica The present invention consists in thecombination, with the parts thus far described, of appliances forfurther controlling the operaytion of the cut-off piston h, includingthe means for charging the chamber m With air under properpressure toinsure the automatic operation of the piston h, as before described.

In order that the piston h may operate prop erly to cut o the dischargeof air from the train-pipe automatically, as has been described, it isnecessary that the said piston should be at the properstarting-pointnamely, at the extreme right-hand end of the cylinderLq2vvihen the engineer operates the valve a to effect a serviceapplication of the brakes. It is necessary, therefore, after eachapplication of the brakes that the piston h should be moved back to therighthand end of the cylinder g2, which is its nor- In order to insurethat this return movement of the piston shall take place promptly andfully, means are provided for reducing the pressure in the chamber m inthe operation of releasing the brakes. For this purpose apassage p isformed leading from the space at the righthand side of the cylinder g2to the seat f2 of the main valve a., and said passage has a port-openingp2 in said seat-f2 adjacent to the exhaust-port opening 2. Forconvenience in construction the said passage is made in part in thebonnet or cover f3 of the valve-cliestf, but for convenience inillustration it is shown as passing more directly to the valve-seat inFigs. 8 and 9 and in somewhat different location with reference to theexhaust-port opening 2. When the valve a is moved to release position,one of the port-openings a7 comes over the port-openings 292 and 2, andthus connects the passagep from the end of the cylinder connectedWith'the chamber m with the exhaust-passage t, so that air escapes fromthe small chamber m and reduces the pressure below that in thetrain-pipe acting upon the lefthand side of the piston h, so that saidpiston h is promptly moved back to the right-hand end of the cylinder.The escape of air from the small chamber m, which is afforded, as hasjust been described, to insure the prompt return of the piston h, isarrested by the said piston h as soon as it arrives at normal position,said piston being provided With a valve r, constructed like acheck-valve and pressed out-Ward from the piston by a springr2, so thatsaid valve r seats in a seat p2, provided for it at the end of thepassage p, and thus closes said passage just before the piston h arrivesatits normal position and retains the said passage closed as long as thepiston remains in normal position either against or very close to theright-hand end or bonnet of the cylinder g2. By these means the pressurein the small chamber m has been reduced to an amount slightly below thatin the trainpipe at the time when the engineer operated the valve a torelease the brakes, and during or after the operation of releasing thebrakes the pressure will rise on the left-hand or train-pipe side of thepiston hto the pressure normally carried in the train-pipe, and it isnecessary that the pressure in the chamber m should be increased to anamount approximately equal to that of the train-pipe in order that thecompressed air in the chamber m may actuate the piston h properly in thenext service application of the brakes. This recharging of the chamber mis effected by a passaget through the piston h, controlled by acheck-valve w, which permits the air to flow through the passage fromthe train-pipe side of the piston into the small chamber m, but Whichprevents any return fioW through said passage from the chamberm into thetrain-pipe. The small chamber 'm will thus be charged from thetrain-pipe through the passage t in the piston to a pressureapproximately equal to thatv in the train-pipe. In the movement of themain valve a to effect an application of the brakes the said main valvecovers the port-opening p2, and thus completely entraps the air in thesmall cham- IOO IIO

IIS

ISO

ber m, so that it may act by its expansiv'e pressure to operate thepiston 7L and control the cut-oit slide 7s automatically, as beforeexplained.

When the main valve a is in running position, connecting the train-pipewith the main reservoir through the excess-pressure valve e, as beforeexplained, there may possibly be some tiuctuations in train-pipepressure, which take place so slowly that they do not affect the brakes,and itis therefore possible that the train-pipe pressure may be reduceda little after the pressure in the small chamber m has been madeapproximately equal thereto, and as there is no equalizing connectionbetween the spaces at the two sides o the piston h the pressure in thechamber m would be in excess of train-pipe pressure and would move thepiston 7i, away from its normal position, in which advanced position itmight remain,and thus interfere with the proper automatic cut-off actionat the next application of the brakes. In order to avoid such operationand always to keep the piston h in substantially its normal position,except when it is intended to move forward in applying the brakes, themain valve a is provided with a pocket or cavity a9, so located as tooverlie the openings p2and t?, and thus connect the passage p from thesmall chamber vn with the exhaust-passage t' when the valve ct is inrunning position, and preferably, also, when it is in lap position, butnot when in service or emergency positions.

The pocket a9 for connecting the passages p and t when the valve is inrunning posi-- tion is made as a cavity in the face of the valve anddoes not communicate with the passage a in the valve, because when thevalve is in running position the openings a7 are over the opening ginthe valve-seat, thus admitting train-pipe air into the passage d, whichmust, of course, at this time be cut ott from communication with theexhaust-passage t.

Escape of air through the passage p from the small chamber m is4controlled entirely by the valve fr in the cutoff-actuating piston h,and Ithe mode of. operation is as follows: If for any cause other thanthe discharge of air by the engineers valve to effect the application ofthe brakes (involving the movement of valve t to service or emergencyposition) the train-pipe pressure should fall below the pressure in thesmall reservoir m sufticiently to produce a movement of the piston htoward the train-pipe side, the said movement would unseat the valve frfrom the opening p3 of the passage p and permit air to escape from thesmall chamberm through the said passage p to the exhaust t and to theatmosphere. This escape of air will continue only until the pressure inthe small chamber m is enough below the train-pipe pressure to enablethe latter to move the piston h back to its normal position, in whichmovement the passage p will again be closed by the valve r, and furtherescape of air from the small chamber will be prevented. By thisconstruction the passage t for charging the small chamber fm is whollyindependent of the main hand-operatedvalve a, and airisadmitted into thesmall chamber when and only when the pressure on the train-pipe side ofthe piston lt is greater than that in the small chamber, and thisconstruction has advantages over the construction ipreviously employedin valves of this type in which there was an equalizing-passageconnecting the spaces at the two sides of the piston h and controlled bythe hand-operated valve d. Where such equalizing-passage is employed,the equalization of pressures may exist without regard to the positionof the piston h, and said piston being normally subjected to equalpressures on'the two sides may possibly be moved by the jars and forcesincident to its use on a locomotive from the normal position at the endof the cylinder g2, and in case it should be so moved it would notoperate properly to close the cut-off 7tat the train-pipe pressuredesired and expected by the engineer. It is possible not only that thepiston may be moved from its normal position while the equality ofpressures on its two sides is maintained, but that by the movement ofthe main valve c after an application of the brakes to running position,either directly or very quickly after its movement to release position,the equalization maybe effected before the piston t has been moved toits normal position, and in such event of course there would be nothingto move the piston to the normal position. By the construction formingthe subject of the present invention, on the other hand, in which thereis no equalizing connec- IOO tion through or around the piston and inwhich the Iiow of air to and from the small chamber m is not controlledby the main handpperated valve ct or any of the working parts of thevalve mechanism there is always insured a suihcient preponderance ofpressure upon the train-pi pe side when the valve is in running positionto retain the piston t in its normal position with certainty, and thesmall chamber m is never wholly depleted of air and is always promptlyrecharged to a pressure approximately equal to train-pipe pressure, soas to be in readiness to actuate the piston 7i, whenever a serviceapplication of the brakes is made.

It is to be observed that the rechargingpassage if is merely aconnection between the air-spaces at the two sides of the piston h,which is controlled by acheck-valve or equivalent device or constructionwhich will permit the air to flow in one direction only through saidconnection, which liow of air is wholly independent of the movements ofthe main valve a and may be wholly independent of the movements ot allof the working or moving parts of the valve apparatus, although in someconstructions it may depend in part upon the position of the piston.Con- IIO sequently it is not necessary that said recharging-passageshould be formed through the piston itself; but it may be any pipe,duct, passage, or space connecting the trainpipe or train-pipe space inthe apparatus at any point with the small chamber m 0r any part of theair-space at the right-hand side of the piston 72.. Suchrecharging-passage might, for example, be made, as shown in dottedlines, Fig. 9, as a pipe 10, leading to the airspace communicating withthe small chamber mfrom the train-pipe or the train-pipe space in thevalve-body and containing a check- Valve w10, which prevents How of airtoward the train-pipe, but permits air to flow from the train-pipewhenever its pressure exceeds the back pressure on the check-valvesufficiently to open the latter. Other constructions involving the samemethod of recharging the small chamber m and of controlling the escapeof air therefrom by the piston 7L are illustrated in Figs. 10, 1l, and12.

For the purpose of recharging the chamber m it is not essential that aduct or passage should be formed through the piston or in the wall ofthe chamber. The construction of the piston and its packing may besuch,as is illustrated in Fig. l0, for example, as to afford a sufficientpassage or space, as indicated at 1520, between the periphery of thepiston and the inner surface of the cylinder to afford connectionbetween the air-spaces at the two sides of the piston through which theair may pass with. sufficient rapidity to recharge the small chamber aspromptly as need be, and the packing of the piston may itself serve asor constitute a check-valve which permits the air to pass through suchconnecting-passage between the piston and cylinder in one directiononly-namely, from the train-pipe to the small chamber*while precludingthe passage of air in the reverse direction.

In the construction shown the piston is provided with a cup-leather orflexible packing-ring w12, having a plane portion clamped tightlybetween the main portion h of the piston and a follower h4, the saidleather packing-ringhaving a cylindrical portion extending from theplane portion over the periphery of the follower h4 toward the side ofthe piston which is subjected to thepressure of the air in the smallchamber m. The cylindrical portion of the said leather packingring w12is normally pressed outward against the walls of the cylinder by thespring-wire w13. Vith this construction the pressure of air upon thetrain-pipe side will tend to separate the cylindrical portion of thepacking-ring from contact with the inner surface of the cylinder, andthus when said pressure is in excess of the pressure on the other sideof the piston it will crowd the cylindrical portion of the packing-ringinward, and thus open a sufficient space between the packingri-ng andsurface of the cylinder for the passage of air to recharge the smallchamber.

The pressure of air on the other side of the piston, toward which thecylindrical or tubular portion of the packing-ring projects, will,however, tend to expand the said tubular packing portion and to press itinto tight contact with the inner surface of the cylinder, so that itwill close the connecting space or passage tightly against the passageof air from the side of the piston subjected to the pressure of air inthe small chamber toward the side subjected to train-pipe pressure. Thusa slightly-loose fit of the piston when provided with a flexibleorcup-leather packing arranged as shown will afford a connecting-passagebetween the air-bodies at the two sides of the piston, and the packingwill constitute a check-valve, so as to permit iiow of air through saidpassage onlyin-the direction from the train-pipe side toward the smallreservoir. Where the piston is also provided with a metallicpacking-ring, as indicated at h3, Fig. ll, the said ring may be providedwith a sufficient space between its adjoining or overlapping ends forthe passage of air past the periphery of the piston, or the said pistonmay be provided with a passage, as shown at i112, Fig. l1, from thetrain-pipe side to the periphery of the piston between the metallicpacking-ring h3 and the flexible or cup-leather packingring lw12.Another' way of providing a passage of this character is shown in Fig.l2, in which the wall of the cylinder is provided with a short passage2513, which when the piston is in normal position at or near theright-hand end of the cylinder extends from the train-pipe side of thepiston to a point over the periphery of the piston between the metallicand flexible packingrings h3 and w12. This passage may be merely agroove in the wall of the cylinder, and it is obvious that the saidgroove might be extended, as indicated in dotted lines at t, to or evenbeyond the edge of the cup-leather packing-ring w12. If thus extended,there might be a return or back flow of air from the small chambertoward the trainpipe when the piston is in extreme right-hand position;but if the train-pipe pressure is reduced as rapidly as is required formaking an application of the brakes the excess of pressure in the smallchamber m will move the piston from the right-hand end of the cylinderalmost immediately, so that the piston will pass the left-hand end ofthe passage t1", and thus prevent such back flow of air, so that withthis construction the piston itself would constitute substantially acheckvalve with reference to the recharging-passage t14. Furthermore, inthe construction illustrated in Fig. 12 if the spring r2 of the valve ris of sufficient force to just overcome the frictional resistance tomovement of the piston when the air-pressures upon its opposite sidesare equal the back iiow of the air through the passage tu will be whollyprevented, the operation then being as follows: Vhen the train-pipepressure is in excess, it

will compress the spring r2, as shown in Fig. 12, thus completelyuncovering the left-hand end ofthe recharging-passage 14; but as soon asthe pressure in the small chamber m becomes almost equal to that in thetrain-pipe the reaction of the spring r2 will carry the pistonbacl; farenough toward the left to completely cover the left-hand end of therecharging-passage im, and thus close the said passage, the piston thusoperating as a che ckvalve in connection with said passage to `permitthe flow of air through the said passage only in the direction from thetrain-pipe to the small chamber on. The term checkvalve is therefore tobe understood as including any construction or contriv'ance forpermitting the flow of air in one direction while preventing flow in theopposite direction. The leather packing-ring may also constitute thevalve which is operated by the piston for controlling the escape of airfrom the small chamber to cause the piston to return to its normalposition, as before explained. In other words, the said cupleatherpacking-ring may be employed as an. equivalent for the valve r. (Shownin Figs. 2, 8, 9, and l2.) Such construction is illus trated in Figs. l0and ll, in which the opening 2930 of the passage p is formed in theinner surface of the cylinder in such position as to be covered andclosed by the cylindrical portion of the leather packing-ring, as shownat r1, when the piston is in or near its normal position. The saidcup-leather thus constitutes a valve by which the piston controls theair-escape passage p, said passage being opened if for any reason thepiston is away from the normal position, (except in the operation ofmaking an application of the brakes by the engineers valve when saidpassage is closed or blanked by the main valve cn) and thus permittingthe air to escape from the small chamber m until the preponderance oftrain-pipe pressure on the other side of the piston forces it back tonormal position, and thereby causes the portion rm of the cupleather toclose the`escape-port p, after which the small chamber m will berecharged to approximately train-pipe pressure through thecharging-passage, which may be either the space between the periphery ofthe piston and its packing and the inner surface of the cylinder, asillustrated in Figs. 10,1 l1, and 12, or may be any suitable passagethrough or around the piston, as illustrated in Fig. 9, controlled by acheckvalve or equivalent, which permits the air to pass from thetrain-pipe to charge the small reservoir, but prevents the return of airfrom the small reservoir to the train-pipe side of the piston.

Obviously the specific construction of the recharging-passage does notin general depend upon the specific construction adapted for the valvefor controlling the escape-passage from the small chamber m.

The operation of the apparatus is as follows: At the end of a serviceapplication the piston hwill bein the position shown in Fig. 9 at adistance from its normal position atthe right-hand end of the cylinderg2, dependent upon the degree of braking force that has been employed inapplying the brakes, and the pressure of the air upon both sides of thepiston 7L will be below the normal train-pipe pressure by an amount alsodependent upon the degree of braking force that has been obtained, thepressure in the supplemental reservoir at the right of the piston being,however, in excess of the trainpipe pressure by about the amountlrequired to overcome the resistance to the movement of the piston h andconnected parts. Then for re leasing the brakes the valve isusuallymoved clear over to the extreme left-hand position, so that theport-opening a7 connects thepassages p and t', or in some cases it maybemoved merely to running position, in which the cavity of connects thepassages p and t', as shown in Fig. 8. In either case-thatis, whetherthe Avalve is carried to what is known as full-release Aposition toconnect the main reservoir directly with the train-pipe or is carried torunning position in which the main reservoir is connected with thetrain-pipe only through the excess-pressure valve e--the brakes Will bereleased by the charging of the train-pipe, and at the same time thepassage p Will be connected with the atmosphere, permitting the air toescape from the supplemental reservoir and cylinder g2 at the right-handside of the piston h until the pressure therein falls enough below train-pipe pressure to have the preponderance of the latter move the pistonto the right, which movement will take place very rapidly, and thuscause the valve r to stop the escape of air from the small reservoir andfurther reduction in pressure therein as soon as said pressure hasfallen only slightly below the pressure then existing in the train-pipe.During this operation the check-valve tu (or w10, Fig. 9) will of coursebe open and the train-pipe air permitted to pass through the passaget(or z510) to the righthand side of the piston, which is open to theatmosphere during the short interval of time required for the piston totravel back to its normal position. so small that such passage of airthrough it does not appreciably reduce the train-pipe pressure,substantially the full effect of which is exerted at the left-handside'of the piston, and consequently produces the prompt movement of thepiston as soon as the pressure on the right-hand side falls slightlybelow the train pipe pressure. The capacity of the small chamber m is sosmall, however, that said chamber will be very quickly recharged throughthe passage t to approximately trainpipe pressure, so that the engineersvalve will be ready for a prompt reapplication of the brakes, ifdesired, immediately after the brakes have been released either bymoving the handle to what is known as full-release The passage t is,however,

IOO

IIO

position or by moving it to running position to perform what issometimes known as the slow release of the brakes. With the constructionheretofore commonly adopted for this type of engineers valve, on theother hand, if the brakes were released by moving the valve to runningposition the equalizingpassage connecting the spaces at the tw-o sidesof the piston h would be opened and unobstructed and the pressure wouldbe equalized upon the two sides of said piston while in the abnormalposition in which it was left at the end of the operation of applyingthe brakes, being the position corresponding to that shown in Fig. 9 ofthe drawings in th'e present case. Such manipulation of the valve isimproper in the case of said prior construction and may cause trouble onthe next application of the brakes, because the cut-Qfjf slide 7o wouldbe in improper or abnormafpositiou, and consequently the engiueer wouldnot open the vent from the train-pipe or it would not be retained openuntil the desired pressure had been obtained, such as would be obtainedby moving the handle to the same position if the apparatus had beenproperly manipulated on the previous release of the brakes. With thepresent construction, however, the valve will operate equallysatisfactorily whether the brakes are released by moving the valve tofull-release position or by moving it to running position to effect theslow release of the brakes, and consequently for this apparatus eithermode of manipulating the valve is proper so far as the action of theapparatus is concerned and the trouble or inconvenience which mightarise fromimproper manipulation of the old form of valve is whollyeliminated.

While the foregoing description has been directed specifically to theconstruction of the engineers valve herein shown and described, it isobvious that the invention is not limited tothe specific details ofconstruction o1' arrangement, but is applicable to any engineers valvehaving an automatic cut-olf operated by a piston or equivalent devicesubjected to train-pipe pressure on one side and to a coperatingair-pressure of the nature hereinbefore described on the other side.

We claiml. In an engineers brake-valve, the combination of the mainvalve adapted to effect the admission of air to and the escape of airfrom the train-pipe; and an automatic cutoff valve for stopping theescape of air from the train-pipe, and an actuating-piston for saidcut-oft' valve subjected to train-pipe bination of the main valveadapted to effect the admission of air to and the escape of air from thetrain-pipe; and an automatic cutoff Valve for stopping the escape of airfrom the train=pipe,and an actuating-piston for said cut-off valvesubjected to train-pipe pressure on one side, and to the pressure of aconfined body of air upon the other side; with a discharge-passage forthe escape of said confined air, and a valve controlling the sameoperated by the piston; and means for closing said passage when anapplication of the brakes is being made; and a passage connecting theairbodies at the two sides of the piston and provided with a check-valvewhich permits the Iiow of air from the train-pipe side only,substantially as described.

3. In an engineers brake-valve, the combination of the main Valveadapted to effect the admission of air to and the escape of air from thetrain-pipe; and an automatic cut-olf.

Valve for'stopping the escape of air from the train-pipe, and anactuating-piston for said cut-off valve subjected to train-pipe pressureon one side, and a chamber containing a conlined body of air actinguponthe other side of said piston; with a discharge-passage from saidchamber and a'valve controlling the same controlled by the piston, saidmain valve having provision for opening and closing said dis-vcharge-passage, when said main valve is in the position for admittingair to, and for discharging air from the train-pipe respectively, andmeans for charging said chamber after air has been permitted to escapetherefrom, substantially as described.

In testimony whereof we have signed our names to this specification, inthe presence of two subscribing witnesses, on the 14th day of March,1902.

ROBERT C. AUGUR. HENRY F. BICKEL. Witnesses as to Robert C. Augur:

JNO. F. MALONEY, H. G. WORKMAN. e Witnesses as to Henry F. Bickel:

C. H. CHAFFEE, G. C. HICKINGBOTHAM.

